GMAC_NITER:2,8
GMAC_ROLL_THRESHOLD:2,4,16
GMAC_BLOCK_SIZE:4096,524288,2097152,8388608
GMAC_STENCIL_DIM_ELEMS:128,256
GMAC_MEMCPY_TYPE:1,2,3
GMAC_MEMCPY_GMAC:0,1
GMAC_XSIZE:4096,65536,262144
